noun
1.
Synonyms: treachery , disloyalty, faithlessness, perfidiousness, treacherousness, treason
Related Word: foul play
Idioms: Judas' kiss
Antonyms: fealty
2.
Synonyms: infidelity , disloyalty, faithlessness, falseness, falsity, perfidiousness, unfaithfulness
Related Word: betrayal, sellout